os7.1.c

#include<stdio.h>
/*
void fcfs(int processes[],int n,int burst_time[]){
    int waiting_time[n],turnaround_time[n],total_waiting_time = 0,total_turnaround_time =0;
    waiting_time[0]=0;

    for(int i = 1; i < n;i++) {
        waiting_time[i] = burst_time[i-1] + waiting_time[i-1];
        total_waiting_time += waiting_time[i];
    }

    for(int i=0; i<n ;i++) {
        turnaround_time[i]=burst_time[i] + waiting_time[i];
        total_turnaround_time += turnaround_time[i];
    }

    printf("First come ,first served (FCFS) Scheduling Algorithm\n");
    printf("-------------------------------------------------\n");
    printf("Process\tBurst Time\t Waiting Time \tTurnarounf Time\n");
    

    for(int i = 0;i < n;i++){
        printf("%d \t%d\t\t%d\t\t%d\n",processes[i],burst_time[i],waiting_time[i],turnaround_time[i]);
    }

    printf("Average waiting time: %.2f\n",(float)total_waiting_time/n);
    printf("Average Turnaround Time: %.2f \n",(float)total_turnaround_time /n);
    printf("\n");
}

void sjf(int processes[],int n,int burst_time[]){
    int waiting_time[n],turnaround_time[n],completion_time[n],total_waiting_time =0,total_turnaround_time = 0;

    for(int i=0;i<n;i++){
        int shortest_job_index = i;

        for(int j= i+1; j<n ;j++){
            if(burst_time[j] < burst_time[shortest_job_index])
                shortest_job_index = j;
        }
        int temp = burst_time[i];
        burst_time[i] = burst_time[shortest_job_index];
        burst_time[shortest_job_index] = temp;

        temp = processes[i];
        processes[i] = processes[shortest_job_index];
        processes[shortest_job_index] =temp;
    }

    waiting_time[0] = 0;

    for(int i = 1;i< n;i++){
        waiting_time[i]=burst_time[i-1] + waiting_time[i-1];
        total_waiting_time += waiting_time[i];
    }

    for(int i=0; i<n;i++){
        turnaround_time[i] = burst_time[i] + waiting_time[i];
        total_turnaround_time += turnaround_time[i];
    }

    printf("Shortest Job first(SJF) scheduling Algorithm\n");
    printf("--------------------------------------------\n");
    printf("Process\tBurst Time\tWaitng Time\tTurnaround Time\n");

    for(int i=0;i<n;i++){
        printf("%d\t%d\t\t%d\t\t%d\n",processes[i],burst_time[i],waiting_time[i],turnaround_time[i]);
    }

    printf("Average Waiting Time : %.2f\n",(float)total_waiting_time/n);
    printf("Average Turnaround Time: %.2f\n",(float)total_turnaround_time/n);
    printf("\n");
}
*/
void roundRobin(int processes[],int n,int burst_time[],int quantum){
    int remaining_time[n],waiting_time[n],turnaround_time[n],total_waiting_time = 0, total_turnaround_time=0;

    for(int i=0;i<n;i++){
        remaining_time[i] = burst_time[i];
        int time= 0;
        while(1){
            int all_processes_completed =2;
            for(int i = 0;i<n;i++){
                if(remaining_time[i]> 0){
                    all_processes_completed =0;
                    if(remaining_time[i]>quantum){
                        time += quantum;
                        remaining_time[i] =quantum;
                    }else{
                        time += remaining_time[i];
                        waiting_time[i] = time - burst_time[i];
                        remaining_time[i]=0;
                    }
                }
            }

            if(all_processes_completed){
                break;
            }
        }

        for(int i=0;i<n;i++){
            turnaround_time[i]=burst_time[i] + waiting_time[i];
            total_turnaround_time += turnaround_time[i];
        }

        printf("Round robin scheduling algorithm\n");
        printf("--------------------------------------\n");
        printf("Process\tburst time\twaiting time\t turnaround time\n");

        for(int i=0;i<n;i++){
            printf("%d\t%d\t\t%d\t\t%d\n",processes[i],burst_time[i],waiting_time[i],turnaround_time[i]);
        }
        printf("Average waitng time : %.2f\n",(float)total_waiting_time /n);
        printf("Average turnaround time: %.2f\n",(float)total_turnaround_time/n);
        printf("\n");
    }
} 
    int main(){
        int n;
        printf("Enter the number of processes:");
        scanf("%d",&n);
        int processes[n],burst_time[n];
       // printf("Enter the burst time for each process: \n");
        for(int i=0;i<n;i++){
            printf("Enter the burst time for each process:\n");
            for(int i=0;i<n;i++){
                printf("Process %d:",i+1);
                scanf("%d",&burst_time[i]);
                processes[i] = i +1;
            }
            int quantum;
            printf("Enter the time quantum fo round robin: ");
            scanf("%d",&quantum);
            printf("\n");
           // fcfs(processes,n,burst_time);
           //sjf(processes,n,burst_time);
            roundRobin(processes,n,burst_time,quantum);
            return 0;
        }
    }